RISK FACTORS FOR RECCURENCE OF PLEOMORPHIC ADENOMA AND POSTOPERATIVE FACIAL NERVE MORBIDITY

Nedim Kasami, Vladimir Popovski

Abstract

Pleomorphic adenoma (PA) is the most frequent tumor of the salivary glands. It is characterized by a tendency to recur, which is determined by the biological characteristics of the tumor as well as the mode of its treatment. Fine needle aspiration cytology (FNAC) is widely used but its sensitivity is controversal up till now. MRI provides information on the exact localization and extent of the lesion, also in the deep lobe and the parapharyngeal space. MRI allows detecting perineural spread, bone invasion and meningeal infiltration. CT should be used for further staging if MRI is not available or contraindicated. Recurrence of the tumor is associated with a high risk of postoperative facial palsy, risk of subsequent recurrence and an increased risk of malignant transformation. Among the factors, the most important are: incomplete excision, intraoperative capsule rupture, myxoid subtype, presence of the satellite nodules and the experience of the surgeon. The aims of the study were evaluation and correlations of histological properties of tumor (it’s size, location, subtype), mode of treatment and rate of recurrence, to compare the incidence of postoperative facial morbidity related to these variables, by using clinical- neurophysiological assessment of facial nerve function post-operatively. This study includes retrospective combined with prospective and descriptive clinical study cases of overall 77 patients with confirmed PA, treated in our clinic in a period from 2016 to 2020. The values of the size and the subtype of the tumor were obtained from the pathohistological findings after the surgery, comparing with preoperative assessment of CT or MRI values. Clinical assessment was based on House–Brackmann scale (H–B), postoperatively and the neurophysiological diagnostic measurement which included surface mimetic muscle electromyography (S-EMG), comparing the affected side with the non-affected one. Multivariable logistic regression analyses and descriptive inferential with binary logistic regression were conducted to identify risk factors for the recurrence, postoperative facial nerve dysfunction, tumor size, location and it`s subtype. A statistically significant relationship was found between the appearance of facial paresis and tumor location in the superficial lobe, size and myxoid subtype. Neurophysiological studies detected clinically silent facial nerve neuropathy of mandibular marginal branch in postoperative period. S- EMG, allows for the evaluation of face muscles reinnervation and facial nerve regeneration. The commonest complications after parotidectomy are temporary or permanent facial palsy and Frey’s syndrome. Tumor location in the parotid superficial lobe upper area, size and myxoid subtype are risk factors that can worsen facial paresis. The knowledge of these complications is relevant for patient´s counseling and to achieve better long-term outcomes.

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